(a) Field
The subject matter disclosed generally relates to microcapsules and processes of making the same. More specifically, the subject matter disclosed relates to silica microcapsule and processes for making the same.
(b) Related Prior Art
Compared with traditional organic materials, inorganic matrices and more specifically ceramics have many intrinsic advantages. In particular, they are biologically inert, intrinsically hydrophilic, and represent higher mechanical strength and thermal stability.
Hollow silicon microcapsules are often synthesized using a templating method (such as disclosed in Chinese patent application No. CN 101708853A) where polysterol polymers (e.g. polystyrene) microballoons are used as templates, and usually yield spheres having diameters of about 500 nm to about 4 μm, which are on the smaller scale for such microspheres
The inventors have developed a range of processes for making microcapsules based on forming ceramic particles using oil-in-water emulsion and sol-gel processes and related technology for the production of hollow microspheres in the range of 0.1 μm to about 1500 μm. The microcapsules of the present invention may be used as density-reducing additive with extremely low density, as low as 0.001 g/cm3, was invented by taking the form of micron-scale core/shell/functional surface type microcapsules, intent on being used in the plastics, composites, rubbers and textiles industries at little or no cost to their performance. The reduction in density or weight lowers the cost of material and transportation. The present invention relates to core/shell/functional surface type reservoirs or microcapsules, which comprise a core (gaseous or hollow) surrounded by a shell (generally solid) composed essentially of one or more silica-based materials and capped with a functional surface with affinity or adhesion to the matrix of plastics or composites or rubbers or textiles. The present invention is introduced into plastics, composites, rubbers and textiles products in their processing stage. Gaseous or hollow microcapsules are dispersed throughout or partially in plastics, composites, rubbers and textiles products as a density-reducing additive to reduce the density of the final products.